In electronics, a choke is commonly used to block alternating-current (AC) signals with frequencies higher than a desired value, while direct-current (DC) signals or low frequency signals are allowed to pass.
In some approaches, when the choke is applied in an electronic device, the choke is useful for eliminating radio frequency (RF) noise from lines and for preventing electromagnetic interference (EMI) and radio frequency interference (RFI) from power supply lines.